Demoniak3D
A tool designed to help developers and technical artists quickly create and prototype realtime 3D solutions: demos, benchmarks, little applications or games. It's also a fantastic tool to start and learn real time 3D programming. Demoniak3D takes a 3D scene description code, located in a XML file, and executes it.
Development: oZone3D Software
Type: Game Design
License: Free Noncommercial

Genesis3D
Open Source 3D Game Development Engine, with a license designed to allow use of the game in commercial, or non-commercial applications for free. 3D rendering environment for all of your real-time 3D needs. Free games making freeware, 3d game design software development online download.

Development: Eclipse Entertainment
Type: Game Design
License: Free Noncommercial

Game Maker
Do you want to develop computer games without spending countless hours learning how to become a programmer? Then you've come to the right place. Game Maker allows you to make exciting 2d computer games, animated graphics, music and sound effects, without the need to write a single line of code.
Development: YoYo Games Limited
Type: Game Design
License: Free Noncommercial

Flight Simulator Screensaver
It displays a group of fighter jets that blast through the sky at high speeds in a variety of 3D environments. There are many configurable options. You can set view angles, cloud cover density, color and speed as well as how many aircraft you wish to fly. Sky color, fog color, and lighting color, they are all customizable.
Development: Longgame Software
Type: Game
License: Free Noncommercial

SketchUp
Whether the games are web-based or created for popular video game units, the race is always on to get the latest and greatest games to market. SketchUp works great for level design because it's fast, accurate, really easy-to-use. Game designers tell us that SketchUp enhances their creativity.
Development: Google Inc. Software
Type: Game Design
License: Free Noncommercial

Autodesk 3ds Max
The Autodesk 3ds Max 30-day trial provides free access to the software for noncommercial use. Animation and 3D graphics students, industry professionals, or anyone interested in breaking into the world of computer graphics (CG) now has the opportunity to explore all aspects of 3ds Max software.
Development: Autodesk Inc.
Type: 3D Software
License: Commercial

RPG Maker XP
You might think it's hard to make a game, but it's a breeze to find your way around RPG MAKER XP. First, make a map that'll serve as the stage for your adventure, then set up your heroes, enemy monsters, items, magic-everything you need to create a good, your own RPG original role-playing games.
Development: Enterbrain, Inc.
Type: Game Design
License: Free Noncommercial

Nebula Device
The leading Open Source 3D game and visualization engine used in dozens of commercial games and professional visualisation applications released worldwide. To save you the effort of building 3rd party libraries, put together pre-built packages for VC7 and VC8, free gaming software download.
Development: Radon Labs GmbH
Type: Game Design
License: Free Noncommercial